The view from here : User-centered perspectives on social network policy

In practice, the legal reasoning regarding the admissibility of social network profiles seems to turn on the question of whether this information is ‘public’, taking a descriptive stance on the issues, and indeed making assumptions regarding the nature of social network disclosure. [...] In deciding whether a plaintiff can expect privacy in her Facebook content, courts rely on several factors such as the social (and therefore ‘public’) nature of Facebook and other networking sites, the size (typically relatively large) of the network within which profile information is explicitly shared, and the extent to which the user limits access to her profile through her privacy settings, in [...] Privacy is not an ‘all or nothing’ proposition, and it is at least possible that a reasonable social network participant might still expect privacy in her profile, despite the social nature of the site or the possibility that she has a large number of Facebook friends who have access to the information that she posts. [...] It is entirely possible that social network participants might not perceive information shared in the social networking context as having entered the public domain, and might instead share with others in the same community a set of standards and norms that preclude the disclosure of this information outside of the original network of contacts. [...] There was general agreement (though not universal support for the practice) that pictures would be taken at any social event, posted to Facebook, and ‘tagged’ to identify the individuals who appear and to connect the picture to the online profile of those individuals.